Fast National ratings for Thursday, August 26, 2010.
 
A double-elimination episode of "Big Brother" gave CBS a big Thursday boost, delivering the night's biggest audience and highest demo ratings.
 
Among adults 18-49, CBS won Thursday night with a 1.9 rating, beating the 1.6 rating for ABC in the all-important demographic. FOX had a 1.1 rating for third, topping NBC's 0.9 rating and the 0.5 rating for The CW.
 
Overall, CBS averaged an estimated 7.272 million viewers to go with a 4.5 rating/8 share. ABC's 3.5/6 was second, still far ahead of the 2.3/4 for FOX and NBC's 2.0/4. The CW trailed with a 0.9/1.
 
"Big Brother" dominated the 8 p.m. hour with a 4.8/9, averaging 8.19 million viewers and a 2.7 demo rating, all tops for the night. ABC's repeat of "Wipeout" had a 3.6/7 for second. FOX was third with a 2.9/5 for a repeat of "Bones," which outdid NBC's "Community" and "30 Rock" repeats. The CW's "Vampire Diaries" repeat was fifth with a 1.0/2.
 
CBS remained in first overall in the 9 p.m. hour with a 4.2/7 for a repeat of "CSI: Crime Scene Investigation." ABC's new "Rookie Blue" was second overall with a 3.8/6 and won the hour in the demo with a 1.7 rating. NBC's repeats of "The Office" and "Community" and FOX's repeat of "Fringe" both had a 1.7/3 for third, leaving The CW's "Moonlight" repeat in fifth.
 
A "Mentalist" repeat had a 4.6/8 and a 1.5 demo rating to take the 10 p.m. hour. ABC's special "Secrets of Your Mind - Why We Do What We Do" was second with a 2.9/5. That left NBC's repeat of "Law & Order: Special Victims Unit" in third for the hour.
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.